This invention relates generally to a novel method and apparatus for cracking nuts. More particularly, this invention relates to a novel method and apparatus for cracking all sizes and species of nuts by the imposition of a substantially axial crushing force on the shell of the nut.
A wide variety of methods and apparatus are known in this art for removing the shell or outer skin from a nut in order to gain access to the interior of the nut to retrieve the meat or edible portion thereof. Some of the methods or apparatus are manual whereas others are automatic in operation. It is into this latter category that the method and apparatus of the present invention falls. That is, it is intended that the method and apparatus of the present invention be utilized to automatically and mechanically crack the uncracked nuts which are supplied to it.
Devices exist in the prior art which radially crush the shells of nuts; however, these devices also have the tendency to shatter the meats as well as the shells. That is, the meats of the nuts may be broken into small pieces. It is well known that whole meats have a greater commercial value than shattered meats of the same quality, and hence a significant economic incentive exists for providing whole nut meats.
In many commercial operations, it is required to sort or otherwise categorize the various sizes of nuts of a given species. One necessity for performing this categorizing operation is that known nut cracking machinery must be set to accommodate nuts of a given size with only a slight tolerance for nuts falling significantly above or below the mean size for the category. This classification for categorizing operation requires both man power and machinery both of which are relatively expensive. Moreover, this intermediate operation delays the processing and marketing of the nut meats providing for a greater opportunity for spoilage of the nuts. Many prior art devices require adjustment to accommodate relatively small changes in nut size in order to operate at satisfactory efficiency.
Other known devices utilize impact or some "hammering" impulse to shatter the shells of nuts being processed. It has been found that machinery utilizing abruptly oscillating masses require much heavier parts in their construction and require a relatively large expenditure in time and money in maintenance and replacement of parts.
Known devices impose a wide variety of forces on the nut to be cracked. For example, some known devices roll the nut while compressing it radially. Other devices impose a slicing force to an edge of the nut to gain access to the meat. It has been found that a preferred technique for cracking nuts is to impose an axial crushing force with a minimum radial component. Moreover, if this axial force is carefully modulated, i.e, if the force on the nut is removed after the shell has shattered, greater satisfactory results obtained.
While such known arrangements have exhibited at least a degree of utility in cracking nuts, room for significant improvement remains. The problems enumerated in the foregoing are not intended to be exhaustive, but rather are among many which tend to impair the effectiveness of previously known methods and apparatus for cracking nuts. Other noteworthy problems may also exist; however, those presented above should be significant to demonstrate that nut cracking methods and apparatus appearing in the prior art have not been altogether satisfactory.